The present disclosure relates generally to information handling systems, and more particularly to techniques for an improved wake mechanism of an information handling system following a resume event.
As the value and use of information continues to increase, individuals and businesses seek additional ways to acquire, process and store information. One option available to users is information handling systems. An information handling system (‘IHS’) generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
To reduce power consumption, various components of an IHS may be placed into a variety of different power states with differing levels of power consumption. For example, video output from a computer system, processor operation, and hard disk drive rotation may be deactivated during periods of system inactivity. More sophisticated power management schemes have been developed and implemented as industry standards including the Advanced Power Management APM) Specification described in the Advanced Power Management (APM) BIOS interface Specification, Revision 1.2, dated February, 1996, and the Advanced configuration and Power Interface (ACPI) standard described in the Advanced configuration and Power Interface Specification, Revision 2.0c, dated Aug. 25, 2003, both of which are hereby incorporated herein, in their entirety, by reference.
Such standards define a variety of operational states depending upon system activity and the amount of power being consumed. For example, the ACPI specification defines various “sleeping” states such as S0–S5. In the S0 state (also known as the G0 state) the IHS is fully on and operational, consuming maximum power. In the S5 state (also known as the soft-off state) the computer system consumes a minimal amount of power. In this state, typically no instructions are executed by a processor included in the computer system, almost all devices included in the computer system are inactive, and the computer system generally awaits occurrence of a wakeup or resume event to transition it to a higher activity state. Awakening from the S5 soft-off state typically requires a complete boot of the computer system because no system context is saved prior to entering S5. As is well known, a basic input/output system (‘BIOS’) of the computer system typically includes instructions configured to cause the computer system to be initialized and the operating system to be booted. The sleep states between S0 and S5 each specify varying amounts of component activity and therefore power consumption. States S1–S5 may have differing wakeup latency times depending upon which devices are inactive, how much computer system context was saved prior to entering the sleep state, and other factors. Power management schemes like APM and ACPI need not have multiple sleep states, but may simply have a fully on state and a state of lower power consumption, such as a soft-off power state.
An Instantly Available PC (‘IAPC’) is a well-known power management technology, which is described in ‘The Instantly Available Power Managed Desktop PC Design Guide’, Revision 1.2, Sep. 25 1998, published by Intel Corporation and is incorporated herein by reference. The IAPC allows computer systems to be accessed quickly without the need for the user to idle through a lengthy boot process. The IAPC enables the user to obtain quick access to the operating system environment by replacing the Shutdown→Boot process with a Suspend→Resume or a Sleep→Awake cycle. One of the suspend states that is entered by a computer system having IAPC is defined as the ACPI S3 state, a low latency sleep state (also referred to as a ‘deep sleep’ state) where the computer system consumes approximately a few watts while in suspend state. The advantage over the soft-off state is that in S3 state, system context is saved in system memory and thus the system, devices and/or applications generally do not need to be reinitialized or reconfigured when the user returns to access the computer system. This typically results in a substantial time saving compared to the boot process.
Today, due to advances in the power and execution speed of information handling systems such as personal computers, the wakeup latency time or resume time has been reduced. Some computer system hardware/software manufacturers are requiring that the wakeup latency time for resuming from an S3 state be reduced to approximately 1 second or less. However, many electromechanical devices of the IHS such as cooling fans may require more than 1 second to wake up and be fully operational following a resume event. The slower wakeup latency time may be caused due to various factors such as inherently higher inertia and/or slower reacting components. As a result, the system BIOS may erroneously detect a mechanical failure because the device may be inherently slow to respond within the required 1 second time period. Traditional solutions have centered on improving the response times of these electromechanical and/or other devices by deploying expensive, fast acting circuits and/or components. This often results in increased product costs and reduced reliability.
Therefore, a need exists for improved accommodation of various devices of an IHS having different wakeup latency times following a resume event. More specifically, a need exist to develop tools and techniques for improving the ability to accommodate varying latency times of these devices without any substantial increases in costs. Accordingly, it would be desirable to provide tools and techniques for an improved wake mechanism of an IHS absent the disadvantages found in the prior methods discussed above.